The present invention relates generally to an agricultural tillage implement, and more particularly to such an implement that provides a tillage system using a combination of cutting disks, tillage points, and leveling disks, with or without a drag harrow or rotary reels, which accomplishes complete primary tillage in one pass. This single pass provides an approach to crop residue management that is more cost-effective than past practices, improves soil tilth, yet requires the least operator time, and still leaves fall surface conditions (roughness) that are level and smooth enough to allow the application of chemicals prior to any additional tillage and allows one pass secondary tillage for a truly planter-ready seedbed.
Single-pass tillage implements providing both shallow and primary tillage in a single pass using disks and chisel points are disclosed in U.S. Pat. Nos. 4,245,706; 4,403,662; and 4,538,689. These machines, however, leave furrows and/or ridges in the soil after use. It has become desirable to leave the surface of the soil as level as possible after tilling in the fall to reduce the amount of soil preparation necessary before planting the following spring. U.S. Pat. No. 5,080,178 discloses a disk leveler for use with a tillage machine such as is disclosed in U.S. Pat. No. 4,403,662.
During the late 1970""s, before the machine shown in U.S. Pat. No. 4,403,662 became available, primary tillage was accomplished principally with moldboard plows. The moldboard plow leaves large slabs and chunks of soil that tend to break down during the freeze and thaw cycles of winter, but this type of plowing requires substantial working of the soil in the spring in order to level the field and prepare it for planting of the next crop. Moreover, moldboard plowing is not an effective remedy for soil erosion, and actually has a tendency to exacerbate this problem.
In recent years, farmers have been looking for ways to decrease soil and wind erosion. The use of a large disk assembly in front of a chisel plow on a parabolic shank has gone a long way toward accomplishing these objectives and also breaks up the hard plow pan (or xe2x80x9csolexe2x80x9d) that is created at the particular depth at which the plow is set to operate, caused by repeated tillage at the same depth over the years. The parabolic shank and winged point do reduce soil erosion, but this practice also may create large chunks of soil, and usually requires substantial spring soil working to prepare an adequate seedbed for planting.
During the 1970""s, the cutter chisel was widely used. It consisted of a chisel plow with a row of coulters to cut the residue ahead of two rows of staggered shanks on thirty-inch centers. These shanks had a four-inch twisted point attached to them to perform the primary tillage. The tip of the point was at approximately a 45xc2x0 angle to the horizontal, sloping downwardly and forwardly from the shank. The worked soil followed the curvature of the generally C-shaped shank that was attached to the chisel plow and was twisted in order to provide a moldboard-type turning action. A C-shaped shank, of the type described, is shown in U.S. Pat. No. 4,403,662.
For early cutter chisel plows, there was a net lateral movement of soil. A machine with, for example, eleven shanks would be equipped with five right-hand and six left-hand twisted points. The result was that a wide groove and a large berm were left after a pass. The machine as shown in U.S. Pat. No. 4,403,662 was an improvement because it left a smaller groove and not as large a berm by using fore-and-aft sets of disks and an improved point.
In U.S. Pat. No. 4,538,689, there is disclosed a winged point mounted on a parabolic shank. That winged point, in the combination shown, creates a large, rough surface similar to the surface of the moldboard plow used during the late 1970""s and early 1980""s. The wings on these points are set at a soil lift angle of approximately 30xc2x0. This lift angle was conventional at the time, but it is an aggressive angle that causes the wings to lift the soil abruptly. In some soils, particularly more compacted soils, the combination of an aggressive lift angle on the wings of the point, together with a parabolic shank, which is designed to lift and heave soil, lifted larger soil chunks and threw them out of the paths of the chisel plow and away from cooperating disks, making it difficult to create a level soil surface after a pass of the machine.
During the 1980""s, farmers desired less tillage to prepare for planting. The furrows left by the chisel shanks had to be filled with the berms that were created between each shank. In order to fill these furrows behind large parabolic shanks, smaller shanks were placed to run shallower and were located midway between the larger chisel shanks. This resulted in smaller grooves on reduced centers. With the development of the disk leveler shown in U.S. Pat. No. 5,080,178, the furrows behind the shanks were substantially filled without leaving sizeable grooves after the shanks had passed, thus improving the levelness or xe2x80x9csmoothnessxe2x80x9d of the surface.
As today""s farming operators are trying to combine multiple tillage operations into fewer passes, while maintaining or improving yields and reducing erosion, Crop Residue Management (CRM) has become a well accepted practice. CRM is a year-round system beginning with the selection of crops that produce sufficient quantities of residue and may include the use of cover crops after low residue producing crops. CRM includes all field operations that affect residue amounts, orientation and distribution throughout the period requiring protection. Tillage systems included under CRM are no-till, ridge-till, mulch-till and reduced-till. A change in tillage and planting operations to increase crop residues on the soil surface has been shown to produce crop yields generally equal to or higher than those produced by systems that leave little or no residue on the field after planting. Additionally, more residue means fewer trips across the field, which translates to lower fuel bills, less soil compaction, and less wear and tear on equipment.
It is an object of the instant invention to provide an agricultural tillage implement employing a series of apparatus to perform one-pass primary tillage. A cutting disk is the first apparatus that works the field. These disks cut the residue laterally (across the machine) and mix the majority of the residue throughout the disk tillage profile. Additional conditioning occurs by knocking residue/stalks over into a prone position with large cast spools between each disk for quicker decay. Next, chisel plow units work the soil to fracture and loosen the soil, providing proper soil aggregate size and air pore space relationship throughout the shank tillage profile. The last apparatus to work the field is a set of leveling disks, or a combination of leveling disks and a rotary reel/drag harrow. The function of these will provide is to reduce clod size and leave the soil level and smooth enough to allow one-pass secondary tillage in the spring. As used herein, primary tillage means deep soil plowing, in an approximate range of nine to fourteen inches or greater. Secondary tillage may be in an approximate range of three to six inches. Finally, a leveler smoothes the surface behind the chisel plow units.
Various previous inventions incorporate the disk-ripper-disk configuration on one machine, but are unable to provide superior leveling and field finish in a wide range of conditions and speeds due to design deficiencies that provide limited operation efficiencies and/or agronomic field output. The operator has had a choice to run slow and do a somewhat adequate agronomic job or run fast (more efficient) and degrade the agronomic performance. These previous inventions using conventional disk blades create too much lateral soil movement causing fields to be uneven, especially at varied and increased speeds over 5.5 mph. These conventional leveling blade designs are inefficient at cutting and penetrating due to deeper blade concavity (where deep concavity is defined by the ratio R/D less than 1.3, where R is the radius of curvature and D is the diameter, both of the disk blade, and tend to throw large mounts of soil laterally. Managing the amount of soil throw is the key to providing higher speed primary tillage with high quality output as defined by a level surface finish.
This type of machine is possibly the most economical configuration available for mulch-tillage application since it combines the operation of a tandem disk with a v-ripper to achieve crop residue management, soil tilth, and seedbed conditioning in one pass. However, an improvement in the fundamental design disclosed herein is necessary to eliminate the compromise between operation efficiency and agronomic field output.
It is an object of this invention to provide an agricultural tillage implement that may be used for primary tillage.
It is another object of the instant invention to provide an agricultural tillage implement that allows proper sizing of soil and residue in one pass, giving uniform distribution of soil and residue for subsequent passes.
It is a further object of the instant invention to provide an agricultural tillage implement that is designed to perform complete tillage of the soil in a single pass while leaving a fairly level surface to reduce the amount of soil preparation required for planting the next season.
It is a still further object of the instant invention to provide an agricultural tillage implement that supports the Crop Residue Management approach to farming.
It is an still further object of the invention to provide an implement that will prepare the crop residue for uniform incorporation into the soil profile while providing soil tilth maintenance (compaction elimination) and leave a level surface with small clods and uniform residue distribution for future planting preparation.
It is an even still further objection of this invention to employ shallow concavity front cutter disk blades to cut and mix soil and residue with optimizing horsepower required resulting in a lower draft primary tillage tool (shallow concavity is defined the ratio (R/D greater than 1.5, R is the radius of curvature, D is the diameter, both for the disk blade).
These and other objects are obtained by providing an agricultural tillage implement employing a series of apparatus to perform one-pass primary tillage. A cutting disk is the first apparatus that works the field. These disks cut the residue laterally (across the machine) and mix the majority of the residue throughout the disk tillage profile. Additional conditioning occurs by knocking residue/stalks over into a prone position with large cast spools between each disk for quicker decay. Next, chisel plow units work the soil to fracture and loosen the soil, providing proper soil aggregate size and air pore space relationship throughout the shank tillage profile. The last apparatus to work the field is a set of leveling disks, or a combination of leveling disks and a rotary reel/drag harrow. The function of these will provide is to reduce clod size and leave the soil level and smooth enough to allow one-pass secondary tillage in the spring.